PACEMAKER BATTERIES Introduction pacemaker o Small electrical device

PACEMAKER BATTERIES

Introduction -pacemaker o Small electrical device that runs on batteries. o Watches electrical signal of our heart and provide the electrical signal if our heart does not do so. o When heart produces its own electrical signal then pacemaker continue to monitor

Mercury cells o Negative electrode - zinc o Positive electrode -mercury liberated from mercuric oxide o Electrolyte -sodium hydroxide. o Outer case –stainless steel.

zn+ + Na. OH ------> Na. Zn. O + H+ (+ive ions with mercuric oxide gives +ive ions of mercury and water) o 2 H+ + Hgo ----> Hg+ + H 2 O (mercury ions combine with incoming electron & neutralized) o Hg+ +e-----> Hg o

Lithium cells o Anode --- lithium o Cathode---iodine o Life span more than 5 years o Discharge time will be low. o It will give low signal when they go beyond a particular level. o Efficiency is high.

Advantages o o o Higher cell voltage. Higher capacity. Greater life span. Smaller size. Operation over a wide range of temperature

Working of lithium cells o Li -------> Li+ + eo I 2 + 2 e- -----> 2 Io 2 Li + I 2 -------> 2 Li. I

Rechargeable batteries o They are not wisely used because they are not reliable. o Galvanic action in these cell evolves gas. o If the cell is sealed these gases must be consumed in balancing reaction. o So it is designed that the rate of evolution of oxygen gas from negative electrode equal to the rate of recombination of with cadmium.

Nuclear cells o Nuclear fuel can deliver enough power to operate pacemakers. o pu-238 produces radiation and hits the container and thus produces the heat. o Thermopile is inserted which converts thermal energy to electrical energy. o Thermopile is stack of thermocouple.

High voltage nuclear cells o Uses radioactive material. o Radioactive material have too much of energy and releases the extra energy (electrons). o It hits the outer surface and makes it negative o The two surfaces are perfectly insulated.

Low voltage nuclear cells o Uses radioactive material. o Here semiconductor is placed between the emitter and collector. o Hence moving of electrons will be slow. o Nuclear cells having long life time. o But the patients are not willing to accept due to danger through radioactive radiation leakage.

External power sources using Telemetry o Here multivibrators are used which generates desired pulses at the rate of 70 beats / minute. o Pulses are used to turn R. F oscillator of frequency 2 MHZ. o Modulated R. F waves are amplified and transmitted through the transmitter coil. o This type is also not liked by the cardiac patients.